696 BULLETIN 50, FNITEB STATES NATIONAL MUSEUM. 



Tieuste differs in relatively much larger bill and longer tail and some- 

 what different style of coloration, the species of Reguloides having 

 two broad whitish wing-bars, some of them having the rump pale 

 yellow and some the inner webs of outermost rectrices white. 



ACANTHOPNEUSTE BOREALIS KENNICOTTI (Baird). 

 ALASKtN WILIOW WAKBLER, 



Similar to^. 5. iorealis^'^ but smaller; color of upper parts decidedly 

 grayer (at least in spring and summer plumage), and under parts less 

 strongly tinged with yellow. 



Adults in spriiig and summer.- — Above plain light grayish olive, 

 becoming more greenish olive on rump and upper tail-coverts; outer- 

 most greater wing-coverts narrowly tipped (on outer webs) with 

 whitish; a narrow superciliary stripe of dull primrose yellow or very 

 pale buffy yellow; a dusky loral streak, broader and darker next to ante- 

 rior angle of eye; upper portion of auricular region deep grayish olive, 

 forming a broad postocular stripe; suborbital, malar, and lower half, 

 or more, of auricular region very pale primrose yellowish or dull 

 yellowish white, more or less clouded with pale grayish olive; under 

 parts very pale dull primrose yellowish or dull yellowish white, shad- 

 ing into pale grayish olive on sides and flanks; axillars and under 

 wing-coverts pale primrose yellow terminally, pale grayish basally, 

 the carpo-metacarpal feathers olivaceous margined with pale yellow- 

 ish; thighs light grayish olive (paler on inner side); maxilla dark 

 brown with paler tomia; mandible pale brown (in dried skins), more or 

 less dusky terminally (sometimes for terminal half); legs and feet 

 clear brownish(in dried skins), the toes rather darker than tarsi. 



Adults in autumn and winter. — Similar to the spring and summer 

 plumage, but more richly colored, the upper parts bright, slightly 

 greenish, olive, the under parts and superciliary stripe pale buffy yel- 

 low or naples yellowish. 



" Phyllopneuste borealis Blaaius, Naumannia, 1858, 313 (Okhotsk Sea, N. lat. 59° 38', 

 E. long! 147° 30', Sept. 15); Taczanowski, Orn. Yost. Sibir., 1877, 26; David and 

 Oustatet, Ois. Chine, 1877, 271; Stejneger, Naturen, 1882, 182 (Bering Island) ; Proc. 

 U. S. Nat. Mus., vi, 1883,- 71 (Bering Island). — Sylvia {Phyllopnemte) borealis Nau- 

 mann, Vog. Deutschl., xiii, 1860, 69, pi. 375, flg. 1. — Phylloscopus borealis Blyth, Ibis, 

 1867, 28; Collett, Proc. Zool. Soc. Lond., 1877, 43^7 (Norway; biography); 

 Seebohm, Cat. Birds Brit. Mus., v, 1881, 40 (excl. syn. PhyUopnemte kennicotti Baird) ; 

 Blakiston, Amend. List Birds Japan, 1884, 56. — Phyllopseustes borealis Meves, Journ. 

 fiir Orn., 1875, 429; Stejneger, Bull. U. S. Nat. Mus., no. 29, 1885, 302 (Petropaulovsk, 

 Bering I., and Copper I., Kamchatka; synonymy, crit., etc.) . — Acanthopneusie borealis 

 Stejneger, Proc. TJ. S. Nat. Mus., xvi, 1893, 636 (Suruga, Japan). — Phylloscopus sylvi- 

 cultrix Swinhoe, Ibis, 1860, 53 (Amoy, China). — Phyllopneuste sylvicultrix Swinhoe, 

 Ibis, 1863, S07.— [Sylvia'] sylvicuUrvi; Gray, Hand-list, i, 1869, 216, no. 3054:.— Sylvia 

 flavescens Gray, Proc. Zool. Soc. Lond., 1860, 349 (Batchian, Moluccas). — Phylloscopus 

 hylebata Swinhoe, Journ. Asiat. Soc. Bengal, xxix, 1860, 265 (Amoy, China). 



